1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef UACCESS_H
3#define UACCESS_H
4
5#include <linux/compiler.h>
6
7extern void *__user_addr_min, *__user_addr_max;
8
9static inline void __chk_user_ptr(const volatile void *p, size_t size)
10{
11	assert(p >= __user_addr_min && p + size <= __user_addr_max);
12}
13
14#define put_user(x, ptr)					\
15({								\
16	typeof(ptr) __pu_ptr = (ptr);				\
17	__chk_user_ptr(__pu_ptr, sizeof(*__pu_ptr));		\
18	WRITE_ONCE(*(__pu_ptr), x);				\
19	0;							\
20})
21
22#define get_user(x, ptr)					\
23({								\
24	typeof(ptr) __pu_ptr = (ptr);				\
25	__chk_user_ptr(__pu_ptr, sizeof(*__pu_ptr));		\
26	x = READ_ONCE(*(__pu_ptr));				\
27	0;							\
28})
29
30static void volatile_memcpy(volatile char *to, const volatile char *from,
31			    unsigned long n)
32{
33	while (n--)
34		*(to++) = *(from++);
35}
36
37static inline int copy_from_user(void *to, const void __user volatile *from,
38				 unsigned long n)
39{
40	__chk_user_ptr(from, n);
41	volatile_memcpy(to, from, n);
42	return 0;
43}
44
45static inline int copy_to_user(void __user volatile *to, const void *from,
46			       unsigned long n)
47{
48	__chk_user_ptr(to, n);
49	volatile_memcpy(to, from, n);
50	return 0;
51}
52#endif /* UACCESS_H */
53